Water control product knob



FIG. 1 is a side perspective view of a water control product knob;

FIG. 2 is a left side view thereof, the right side being the same as the left side;

FIG. 3 is a top view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a bottom view thereof. 

The ornamental design for a water control product knob, as shown and described. 